Learning Forum

[Abubakar]

Can anyone please tell me the basic difference between steady state simulation, pseudo transient simulation and transient simulation? nI know how steady and transient simulation works but I don't how this pseudo transient simulation works and also under what condition we should choose pseudo transient simulation? TIAnnThank you,nAbubakar khan n

[Karthik R]

Hello,nPseudo transient is an implicit under-relaxation method where the time-step is used to under-relax the solution. This is used only for steady-state simulations for the pressure-based coupled solver. nTo understand this better, I recommend that you look into the following links from the Fluent Theory Guide.nI hope this answers your question.nKarthik

[Abubakar]

Sir, I will go through the Fluent Theory Guide to understand Pseudo transient better, but my question is why do I need to run Pseudo transient simulation why can't I settle with Steady state or transient state? Can you give some examples where I have to run Pseudo transient simulation.n

[Rob]

Read the solver section: that'll explain what the pseudo transient setting means in the solver. Note, this is distinct from steady cases which show some transients in the results which are also referred to as pseudo-transient: someone decided to re-use the term..... n

[Abubakar]

sir, just by looking at the Pseudo transient under relaxation expression (please see the attachment) , it's very difficult to understand how exactly it works so, can you please provide some more information or article on the same? TIAn nThanks,nAbubakar khan n

[Rob]

That's all we can share due to the export rules we work to. Default time scale factor is 1, I find 0.1 to be stable for most applications I work with. n

[DrAmine]

Please check open literature to learn about time marching methods for solving steady state Equations.n

[Abubakar]

Any reference on the above? TIAn

[Rob]

I found several possibles using that largely neglected tool called Google. Otherwise read the Theory Guide and there may be references there, typically [123] as links to the reference section. n

[DrAmine]

Google is a good tool.n

[Abubakar]

Thanks sir & sirn